Prevalence and severity of microbleeds in a memory clinic setting

Objective: To determine prevalence and severity of microbleeds (MBs) in a large cohort of patients attending a memory clinic. Methods: The authors consecutively included patients attending their memory clinic between January 2002 and April 2005. They analyzed prevalence and number of MBs according to demographic, diagnostic, and MRI data. Results: The authors included 772 patients (53% men, age 66 +/- 11). One hundred twenty-seven patients (17%) exhibited at least one MB. The prevalence differed according to diagnostic groups (p < 0.0001): Sixty-five percent of patients with vascular dementia exhibited MBs vs 18% of Alzheimer disease patients, 20% of mild cognitive impairment patients, and 10% of patients with subjective complaints. The presence of MBs was associated with age, white matter hyperintensities, lacunar infarcts, and infarcts. Conclusion: The prevalence of microbleeds (MBs) in a large cohort of patients attending a memory clinic is higher than previously described in community samples and lower than reported in stroke patients. This finding of a relatively high proportion of MBs in Alzheimer disease and mild cognitive impairment provides further evidence for the involvement of vascular factors in neurodegenerative diseases such as Alzheimer disease.